Tool for removing cable insulation



Dec '22, 1970 HORROCKS 3,548,690

TOOL FOR REMOVING CABLE INSULATION Filed March 4, 1968 5 INVENTOR. 6 J

BY v A4477; HOFFMAA/V, mu/4 ////4/z United States Patent O '"ice TOOL FOR REMOVING CABLE INSULATION Raymond G. Horrocks, 'Parkview, Ohio, assignor to The Scott & Fetzer Company, Cleveland, Ohio, a corporation of Ohio Filed Mar. 4, 1968, Ser. No. 710,012 Int. Cl. H02g 1/12 US. Cl. 81-95 3 Claims ABSTRACT OF THE DISCLOSURE A tool for removing insulation from an electrically conductive cable including a body having a bore with a close sliding fit with the conductor of the cable and'a blade having a cutting edge positioned to extend across the insulation from almost but not quite in contact with the conductor.

BACKGROUND OF THE INVENTION The prior art most nearly pertinent to this invention and known to me is my patent No. 3,225,629.

SUMMARY OF THE INVENTION A tool embodying this invention includes a body having a longitudinal bore which is of such a diameter as to have a close sliding fit with the cable and to guide the tool in its axial rotational movement relative to the cable while the insulation is being removed. A blade is so positioned on the body that its cutting edge extends across the insulation from a point close to a circle substantially in contact with the conductor.

The cutting edge should sever the insulation but should not nick the conductor. Such sizing of the bore and conductor and such positioning of the blade will prevent nicking of the conductor and yet remove substantially all the insulation from the conductor.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a tool embodying the present invention with a portion of a cable positioned relative thereto preparatory to removal of the insulation from the cable;

FIG. 2 is a side elevational view of the tool of FIG. 1, partly in section and showing a portion of the cable as the insulation is being removed;

FIG. 3 is an end elevational view of the tool of FIG. 2;

FIG. 4 is a fragmentary, side elevational view of the tool of FIGS. 1 and 2; and

FIG. 5 is a view similar to FIG. 3 but showing an alternative position of the cutting blade.

FIGS. 1 to 4, inclusive, disclose a preferred embodiment of the present invention. In these figures the hand tool is shown as comprising a body 1 having a longitudinal bore 3 and an end surface consisting of a portion 5 which is normal to the axis of the bore, a curved throat portion 7 which intersects bore 3 and an inclined blade supporting portion 9 which intersects with the curved portion 7.

A cutting blade 11 is adjustably secured on inclined surface 9, as by a cap screw 13, and has a cutting edge 15 which is positioned on a diameter of the cable and extends from the bore 3 across the insulation. The blade overhangs the curved throat surface and preferably projects a short distance, for example, about from portion 5 of the end surface of the tool body, all as is better shown in FIG. 3. The cutting edge has a small clearance or rake, for example, about 3. The blade serves to sever the insulation and direct it along curved surface 7 and away from the tool.

The diameter of bore 3 is only slightly larger than the overall diameter of the conductor 17 of the cable, the insulation of which is shown at 19 in FIGS. 1 and .2. The

3,548,690 Patented Dec. 22, 1970 conductor may consist of wires or strands which lie in contact with one another and within a circle which touches the outermost surface portions of the outer strands. Since it is important'to avoid nicking of the conductor and desirable to remove substantially all the insulation from the conductor, it should have a close slidin fit in bore 3. To that end the diameter of the bore 3 should not exceed the diameter of the conductor by more than about 0.005". The cutting edge 15 of the blade should be spaced just out of contact with the conductor, for example, about 0.006" from the nearest part of the conductor. When the bore and conductor are of such sizes the conductor will be so positioned in the bore that the cutting blade will just clear the outer surfaces of the strands even though the conductor is not truly concentric with the insulation. Any insulation which may lie between outer surfaces of strands of the conductor will not be severed by the cutting blade but can be readily removed by hand in a subsequent operation.

It is believed that the operation of the tool of FIGS. 1 to 4 will be understood from the drawings and the foregoing description but it may be succinctly described as follows:

With the cutting blade 11 positioned on the tool 1 as shown in FIGS. 1 to 4 and with the insulation removed from one end of the cable far enough to admit insertion of the exposed end of the conductor into the bore, the tool is rotated and moved axially relative to the cable. The blade 11 cuts the insulation and directs it in the form of a strip or spiral against curved throat surface 7 and thence away from the tool. When the insulation has been removed from the desired length of conductor, the tool may be pulled off the conductor 17.

It is not necessary that the edge of the cutting blade should be positioned on a diameter of the bore and tool as shown in FIG. 3 although that is a preferred positionin FIG. 5 shows a position of the tool at approximately to the position shown in FIG. 3. In FIG. 5 the edge of the cutting tool extends at right angles to a diameter of the cable and from closely adjacent to the conductor to the outer circumference of the insulation.

It will be understood that the cutting blade may be located in any position between those shown in FIGS. 3 and 5 if desired.

Having thus described this invention in such full, clear, concise and exact terms as to enable any person skilled in the art to which it pertains to make and use the same, and having set forth the best mode contemplated of carrying out this invention, I state that the subject matter which I regard as being my invention is particularly pointed out and distinctly claimed in what is claimed, it being understood that equivalents or modifications of, or substitutions for, parts of the above specifically described embodiment of the invention may be made without departing from the scope of the invention as set forth in what is claimed.

What is claimed is:

1. A hand tool for removing insulation from the conductor of an electrically conductive cable which comprises an elongated body having a longitudinal bore, the diameter of the bore being only slightly greater than that of the conductor so that the latter will have a close sliding fit in the bore, one end of said body having a surface normal to said bore, a curved throat surface intersecting said bore and an inclined blade-carrying surface intersecting said curved surface, and a blade positioned on said inclined surface with its cutting edge extending across the insulation from a point almost in contact with the conductor.

2. The combination of elements set forth in claim 1 in which the edge of the blade overlies the said curved surface.

3. The combination of elements set forth in claim 1 in which the cutting edge of the blade lies on a diameter of the cable and extends across the. insulation fromithe bore.

References Cited UNITED STATES PATENTS 4 FOREIGN PATENTS 529,066 11/1940 Great Britain 819.5(C) 768,853 2/1957 Great Britain 81-9.5(C)

THERON E. CONDON, Primary Examiner R. V. PARKER, JR., Assistant Examiner 

